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Multimedia technology opens windows on engineering tasks.

Long regarded as a technology for creating eye-pleasing presentations, multimedia is showing that it can inform as well. The integration of raster, vector, text, video, and audio data can add new dimensions to design and manufacturing processes.

Multimedia has been I scoffed at by "serious" computer users and even' some vendors as being a soft technology, mainly suited for entertainment and education. But while mechanical engineers have largely ignored multimedia, development of hardware and software continues to grow as designers and manufacturers discover the benefits of presenting data in interactive formats.

The integration of text and graphics, popularized by the Macintosh from Apple Computer Inc. (Cupertino, Calif.), sparked the initial interest in multimedia. Video boards and sound boards--such as the IMS-1000 card from Image Manipulation Systems (Forest Lake, Minn.) for integrating live video, true-color graphics, and text on IPC and Sparc workstations from Sun Microsystems Inc. (Mountain View, Calif.)--increased the types of data that could be presented on a single platform. As computers became more capable, they could draw from and process a growing number of data sources.

Features designed to ease multimedia presentations are showing up as standard features on current computers. The Iris Indigo and new Indigo2 Extreme workstations from Silicon Graphics Inc. (Mountain View, Calif.) were designed specifically as multimedia platforms. The CPU motherboards support 18-bit stereo sound, analog microphone input, and serial digital input--two tracks on the Indigo and six on the Indigo2. Both systems have a video bus directly integrated with the graphics CPU for combining graphics and video, although the video cards themselves are optional.

The Indigo Magic multimedia tool kit permits users to combine and edit video, graphics, and audio. The audio editor has a CD-player-like on-screen interface, and the video and graphics editor has a VCR-like interface. Multimedia presentations can be printed to video by attaching an Indigo to a VCR with standard cables. "Multimedia is a mechanism to convey data more expressively," said Doug Dennis, Silicon Graphics' application manager for mechanical products.

Learning the Ropes

Computer-based training is one traditional application of multimedia technology. Intergraph Corp. (Huntsville, Ala.) has developed a computer-based training aid for its I/EMS CAD system (I/CBT-EMS) that employs multimedia technology. The instructional package includes a conceptual presentation consisting of routines downloaded from I/EMS with added narration, music, and illustrative graphics. The final part of the course involves a live link to I/EMS where the user responds to queries in a controlled environment. I/CBT-EMS allows the user to go at his or her own pace and to concentrate on select portions of the course.

Deane Dayton, a training specialist at Intergraph, developed I/CBT-EMS to serve as an alternative to customers sending prospective I/EMS users to Huntsville for training. "The typical customer spends $1000 a week plus travel and lodging for training each user," Dayton said. "The economics of computer-based training are favorable." The computer-based course, which may require several days to a week to complete depending on the user's pace, costs $900 and requires a CD-ROM drive, a Clipper workstation, and a copy of I/EMS. Dayton said that in the long run it is significantly less expensive to train users with multimedia than it is with live instructors, since it is a one-time expense and many people can learn from it.

I/CBT-EMS incorporates most aspects of multimedia, except live-action video. The conceptual portion of the course is divided into about 40 segments dealing with different functions of I/EMS. Each quasi-animated segment is narrated and may involve activities that are performed via a live link to I/EMS. According to Dayton, experience has shown that narration combined with good graphics results in better retention by users than printed instructions alone do. To evaluate how well a user understands the system, the number of mouse clicks is monitored and audio feedback is given.

The program has proven useful as a learning tool for new users and as a tool to make transitions to newer versions of I/EMS. While reaction to I/CBT-EMS has been favorable, Intergraph has no plans to expand computer-based training to any of its other applications. One reason is that EMS is the most used of Intergraph's software packages and thus lends itself to "canned" training. Less-used packages would not be as easy to document. Another reason is the effort required to put a multimedia package together. A script must be written, graphics and audio timed, and the CD-ROM professionally mastered. It took about a year to develop the two hours of audio material and 1000 different graphics to make I/CBT-EMS.

Integrated Presentations

Some companies specialize in making multimedia presentations to engineers. CDI Computer Services (Detroit), for example, integrates computer graphics, solid modeling, kinematics analysis, and live video into multimedia productions for the Big Three automakers. In the company's visual engineering lab, multimedia specialists take in surface wireframe files and blueprints from their clients. A variety of software packages are used on 12 Unix workstations to create different aspects of the presentation. Software includes Alias Studio from Alias Research Inc. (Toronto, Ontario) for surface rendering; Con-. ceptstation from Aries Technology (Lowell, Mass.) and Catia from Dassault Systemes (Paris) for solid modeling; and Adams from Mechanical Dynamics Inc. (Ann Arbor, Mich.) for motion analysis. The Composer system from Wavefront Technologies (Santa Barbara, Calif.) is used to produce the final output and transcribe the results to VHS videotape.

Most of the work produced by CDI is used for presentations. However, Michael Lord, a technical support specialist at CDI, said multimedia is also used in support of more traditional mechanical engineering applications. In one project, CDI produced a crash study with live-action video and computer-generated animation side by side. Frame-grabbing was used to select a series of stills from a client-supplied video of an actual crash test. Finite element and motion analyses were modeled on each frame using Nastran from MacNeal Schwendler Corp. (Los Angeles) and Adams respectively as solvers. When run jointly as a multimedia presentation, this permitted engineers to examine the evolution of impact-induced stresses in direct relation to an actual flash event.

According to Wavefront Technologies, animated pictures from CAD, motion analysis, and FEA results can be used to visualize engineering data in new ways. CAD data can be texture-mapped to produce realistic renderings or animated using key-frame animation. With this technique, the user needs to specify the start and finish of a particular action and the visualization system generates the motion in between. If complex motion is desired, more key frames can be specified. Likewise, post-processing results from motion and numerical analyses can be applied to the animation.

By interpolating different types of data and selectively enabling them during different stages of the animation, nearly any realistic or interpretive result can be generated. For example, an exterior component of an operating assembly may be made to become transparent during the course of an animation to reveal the interior mechanism.

Wavefront Technologies recently developed the Entry-Level Composer video-production software package. The system is targeted at users who are new to the concept of recording presentations on video tape, including engineers.

Keeping Track

A rapidly growing engineering application for multimedia is in the area of document management. A few software developers have determined that the best way to present the vast array of documentation required for the assembly of manufactured goods is through a multimedia format. Information sources may include ASCII text, vector graphics, raster images, files from technical publishing systems, scanned-in sketches, and photos. According to Cimlinc Inc. (Itasca, Ill.), work instructions for a given year may total 50,000 pages for a small factory and at least 2 million for a Fortune 500 installation.

Cimlinc has developed the Linkage multimedia work instructions software to compile, manage, and communicate data from these multiple sources on Unix workstations and X-Window-compatible terminals and personal computers. Linkage features a ScriptLink macro programming language for developing scripting routines. Programmable electronic templates allow the creation of electronic forms to manage and display multimedia data. Scripted procedures automate information gathering and manipulation of the templates. A library of dynamic data links accesses live data from multiple sources. In addition, Linkage has a number of text, graphical, and geometry editors.

The CIMplan package from Gerber Systems Corp. (South Windsor, Conn.) is a multimedia tool for shop-floor documentation. According to Robert Houlihan, business unit manager, CIMplan is intended for use by process planners, manufacturing engineers, and quality-control engineers to assist in shop-floor documentation.

CIMplan can receive raster, vector, text, and video input via the standard file format for each data type. On-line graphics tools allow the addition of sketches and annotation of drawings using elements familiar to users of most CAD packages. Data bases are created from standard and user-defined form-based input. Sheets containing completed forms constitute a data base that can be queried. The software runs on HP 9000 series 400 and 700 workstations from Hewlett-Packard Corp. (Palo Alto, Calif.), Sparcstations from Sun, and Silicon Graphics Personal Iris and Indigo platforms. In addition, CIMplan can be viewed from X-Window platforms.

Tuning In

Last February, when the Multimedia division of Autodesk Inc. (Sausalito, Calif.) introduced its Cyberspace Developer Kit (CDK) for creating virtual-reality applications, the definition of multimedia moved further out of focus. Virtual reality does not typically spring to mind in the context of multimedia. However, CDK can read AutoCAD DXF or 3D Studio .3DS files and build a 3-D interactive environment complete with audio components and speech-recognition-assisted input. The CDK tool kit provides programmers with a C++ object-oriented language to develop virtual presentations of CAD data. A user can stroll through virtual-reality-generated houses and molecules on an IBM-compatible PC monitor or opt for total immersion with a full-blown headmounted display. The developers say that the variety of input and output formats supported by CDK qualifies it as a multimedia application.

"Virtual reality, like multimedia, suffers from overexposure," said Richard Dym, general manager of Autodesk's Multimedia division. Dym said the visualization and "wander through" capabilities of virtual reality make it an excellent multimedia presentation technology. "CDK is an enabling technology to make virtual reality an integral part of CAD in the future," he said.

What separates CDK virtual reality from presentation-style technologies is the degree of interactivity it provides for users. Objects not only have geometry and dimension, but can be assigned physical properties such as mass, weight, friction, and spring. Thus when users interact with the objects, whether through a mouse or a more exotic input device such as a data glove, the objects respond to user manipulation according to their defined physical properties.

While Autodesk has brought practical virtual reality to the PC-DOS platform, practical mechanical engineering applications have not yet been devised. CDK, which retails for $2500, widens access to virtual reality but does not respond to specific user demands in the mechanical design area. Rather, Autodesk is hoping that imaginative engineers and vertical application developers will excite demand. One sample application permits users to perform a virtual assembly operation. Components designed in AutoCAD and exported to CDK can be manipulated via handheld sensors with voice-activated gripping functions.

Interest in virtual reality presentations of CAD data is growing. A collaborative effort between the Institute for Simulation and Training at the University of Central Florida (Orlando) and MicroGreen Inc. (Gainesville, Fla.) has resulted in the Virtual Environment Navigator package for creating virtual reality simulations from AutoCAD and other DXF-compatible CAD systems. The Navigator permits users to fly through 3-D space in real time, edit virtual simulations in progress, write scripts for actions, record actions, and save and restore virtual worlds for future use. A ray-tracing renderer is included for producing high-quality images of finished environments. Simulations can be output to video and stills. Beta versions of Navigator are available beginning at $2000.

The importance of high-quality CAD graphics and expressive postprocessing in analysis systems indicates that mechanical engineers are becoming as interested as any computer user in how information is conveyed. Multimedia systems for training, presenting data, documenting processes, and developing realistic simulations are being used by engineers to improve not only the appearance of their work, but its accessibility. While multimedia is not yet taken seriously by all engineers, many are finding it a useful technology for complex tasks.
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Author:Puttre, Michael
Publication:Mechanical Engineering-CIME
Date:Apr 1, 1993
Words:2041
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